It is known to prepare bisphenols, e.g., Bisphenol A, by continually reacting, in a reaction zone, at least 2 moles of a phenol with a carbonyl compound in the presence of an acidic ion-exchange resin. The reaction zone effluent is a mixture of unreacted carbonyl compound, phenol, water, bisphenol and reaction by-products. Some of the bisphenol and phenol may be in the form of an adduct. It is possible to remove all of the carbonyl compound and water and a part of the phenol from the reaction zone effluent and to recover the bisphenol from the remainder of the reaction zone effluent, e.g., see U.K. Pat. No. 883,391.
It has now surprisingly been found that the concentration of bisphenol in the remainder of the reaction zone effluent may be substantially increased without adversely effecting the properties of the acidic ion-exchange resin or of the recovered bisphenol if a part of the remainder of the reaction effluent is recycled to the reaction zone.